Mackie HR824 hello, The woofer sound is muted (woofer is ok and amp also?) tweetersound ok, the signal route is muted somewhere inside. Please let me know,,,a solution (i am technician electronics and have no schematics) regards, luc bertels

Try Parts Express; they have a speaker repair service.
http://www.parts-express.com/speakerrepaircenter

This is not a powered mixer and so you must connect a power amp to the "line level" outputs of the mixer. Other "no output" problems could be related to buss assignments and other signal routing issues. Check for output by connecting "Main Out" left or right to a guitar amp input instead BUT turn all volumes down to zero before conductiong this test as guitar amps are designed for "Microphone" level inputs. Owners and Hookup manuals can be found here...

http://www.mackie.com/products/1604vlz3/

Start with the woofer speaker, and check with a multimeter.

If it is Ok, check/replace the amp module.

It could be 2 things:

*Blown Speaker or,
*Fried power amp output stage of woofer, since this speaker operates as a bi-amplified system it has separate amps for woofer/tweeter...

Some sort of feedback. Try grounding the input or connecting a source that is silent. If it still does it, time for the repair shop. This may be close to the schematic:

http://elektrotanya.com/mackie_swa1801_sch.rar/download.html

Scroll down to the link "Get Manual" and click to download a compressed file with two parts. One is the electronic crossover, the other is the power amp.

There is a mute control if signal is not present and also a gain limiter. This may take some troubleshooting by an experienced electronic tech. I would look for something wrong in these two parts of the circuit.

Put a sound system between them and the TV, or better yet get the TV-audio from the Cable/SAT box in digital.

If you disconnect the signal leads and the hum is away, it's probably a groundloop problem, or your equipment is generating the hum.
If it does not go away, the amps are defective

I suggest, go out and buy a heavier duty 18 and replace it.